Thermoresponsive fuse



Dec. 31, 1940. RQ N 2,226,744.

THERMORESPONSIVE FUSE Filed 001;. 8, 1938 Patented Dec. 31, 1940 UNETE STTES ATENT OFFICE.

THERMORESPONSIVE FUSE Application October 8, 1938, Serial No. 233,901

4 Claims.

This invention relates to improvements in a thermoresponsive fuse, and is more particularly directed to a type employed in connection with a temperature responsive apparatus, such asfire extinguishers, or the like.

V In various types of temperature responsive apparatus, means are employed for retaining the apparatus readily releasable, and it is in this connection that my device is employed and illustrated.

Very frequently where a fuse is employed for this purpose in either the compression or tension type of apparatus, that is where a push or pull type of fuse is required, the fuse is usually constructed of relatively thick material to withstand the strain to which it is subjected and is, therefore, not as susceptible to heat as when constructed of light material.

It is the primary object of the present invention to overcome the above objections and to construct a fuse which is exceptionally strong while being light in construction, and which may be employed with an apparatus of the compression or tension type.

A further object is the provision of a fuse having relatively few parts arranged and constructed as a unit to be easily applied to an apparatus, and which may. be flexed while applying the same, or while in position without reducing its strength or rendering it inoperative for release at a predetermined degree of heat.

A further object is the provision of a fuse constructed of few parts and retained together by readily fusible solder .and of such flexibility that it will readily conform to set itself to-the desired position when attached to retain an apparatus in readily operable position.

And a further object is the provision of a fuse of dual releasable construction to enhance its ability for a positive release when subjected to the proper degree of heat.

Other and further objects will become apparent from the ensuing description and are more particularly pointed out in the appended claims.

Referring to the drawing:

Figure 1 is a plan View showing the preferred form of my improved fuse.

Figure 2 is a perspective View of the same.

Figure 3 is a view similar to Figure 1 showing 0 the fuse released with the restraining means partially moved out of position to illustrate its operation.

Figure 4 is a plan View illustrating the fuse W of Figure 1 as attached to the apparatus and conforming therewith.

Figure 5 is a detail perspective view of a modified form of fuse in which the restraining means coacting therewith is attached outwardly thereof.

Figure 6 is a perspective view similar to Figure 5 illustrating the retaining means attached thereto in another manner.

Figure 7 is an enlarged partial perspective view of restraining means having contact with the inner and outer faces of the fuse body; and

Figure 8 is a detail perspective View of the restraining means shown in Figure 7.

In the embodiment of the invention shown in Figures 1 to 4, inclusive, the fuse body It] is constructed of a pair of relatively thin strap members II and I2, respectively, which are preferably identical in shape, being each formed to provide semi-circular formations I3-l3- and I l-l4, respectively, and discontinuous aligned surfaces l5 and I6, respectively, so that when in contact with each other, the semi-circular formations l3 and I4 will provide relatively large openings I1 and [8, respectively, at near each end thereof. In each of these openings l1 and I8 is positioned ,a hollow member Iii-l9 and the parts are then retained in position by readily fusible solder 20, which extends between v the straps l l and I2 and around the hollow members Iii-I9. When completed as above described, thefuse I B then has a shank 2| extending between the hollow members Iii-l9 and semi-circular formations l3 and M which serve with the hollow members as restraining means While the fuse is attached in operative position to the apparatus. The freeends 22 and 23 of the straps are soldered together and assist in retaining the hollow 35 members in the openings 1'! and I8 and these free ends also serve with the hollow members as means for conducting heat to the body of the fuse. The hollow members may be of any desired shape and of a length to extend an appre 40 ci'able distance outwardly on either side of the strap members Hand l2 to more readily conduct heat through the fuse to release the same.

My fuse is applicable to all kinds of apparatus in which a part is to be released when a certain 45 temperature is attained. These devices, such as automatic fire extinguishers, sprinkler heads, fire alarms, fire doors, etc., all employ fusible means, usually a link which connects and retains a pair A of operating arms of the device readily releasable. The arms of these devices are normaly retained under tension and when released, render the device operable.

With a fuse constructed in the manner above described, it will be noted that when applied to' the operating arms of a temperature responsive apparatus in the manner shown in Figure 1, the bifurcated tensioned arms A-A' thereof will receive the shank 2| of the fuse I and will engage the semi-circular formations l3-I3 and I l-l4 which serve with the hollow members .as restraining means or stops for holding the arms A-A in tensioned position.

When the device is applied to an apparatus having a pair of engageable arms (Fig. 4), the bifurcated arm B-B thereof exerts a pressure in one direction on the fuse and .arm B" exerts a pressure in the opposite direction. The shank 2| of the fuse is engaged by arm B" and the semi-circular formations I3 and M are engaged by arm B-B. When the fuse is thus attached, the pressure exerted thereto will tend to bend the same and will force the semi-circular formations of the fuse into engagement with the sides of arm B" and the hollow members l9-l9 within these semi-circular formations will serve as restraint means in the manner shown in Figure 1, although the fuse itself is bodily bent to conform with the arms of the apparatus to which it is attached.

While the fuse is attached to the bifurcated arms A-A shown in Figure 1, a straight tensile strain is exerted on the straps H and I2, so that when subjected to a predetermined degree of heat, the free ends 22 and 23 thereof will conduct the heat to 'the straps H and i2 and the hollow members will permit the heat to pass therethrough to dissolve the solder and release the fuse, thereby releasing the arms A-A of the apparatus to force the hollow members l9-l9 outwardly therewith. In Figure 3 is illustrated the position the fuse assumes when released, the hollow members being moved to near the ends of the straps and the straps as being straightened or ironed out during the releasing movement of the arms of the apparatus. As the straps H and I2 are relatively thin, they will be ironed out in a relatively straight line during this outward movement of the arms A-A', permitting of an unrestrained release of the apparatus.

In Figures and 6, the modified forms disclosed therein comprise a fuse IUB having a pair of relatively thin strap members Ila and [2a which are formed at 24-25, respectively, to provide an opening 26 intermediate their lengths when assembled, and the free ends 21-21 extending outwardly on each end thereof are in face to face relation. A pair of U-shape'd clips 28-28 is then positioned over the ends 21-21 and a readily fusible solder is caused to flow between the adjacent surfaces of the straps I la-l 2a. and between these straps and U-shaped clips 28-28 to retain the parts in position .as a unit. The solder is designated as 28a.

In Figure 6, the U-shaped clips 28-28 are illustrated as attached to the ends 21-21 of the fuse body IDB in a vertical manner, in which the clips extend transversely of the ends and are soldered together in the same manner as described for Figure 5.

In this type of fuse, the arms of the temperature responsive apparatus extend into the opening 26 and exert an outward pressure to the ends 21-21 and clips 28-28 attached thereto, and the clips serve as restraintmeans for withholding the pressure exerted bythese arms. Likewise in Figure 6, the pressure tothe fuse is exerted outwardly and 'while' the clips 28-28 extend transversely of the ends 21-21, they serve in the manner as illustrated in Fig. 5, for withholding the outward strain exerted thereto by the arms of the apparatus.

In Figure '7, only one end of the fuse is shown in which the straps HB and HE thereof are formed in the same manner as that described for Figs. 5 and 6, that is, when assembled providing an opening 29 intermediate its length for receiving the arms of the apparatus to which the fuse is attached, but in this instance, the straps MB and I2B havetheir adjacent faces in spaced relation with respect to each other. A clip 30,which is preferably formed in the shape of an inverted w having outer depending legs 3l-3I and a depending leg 32 intermediate the legs 3l-3I. This intermediate leg 32 extends between the free ends 33-33 of the straps HE and |2B and serves to hold them in spaced relation with each other, while the legs 3 l-3I engage the outer surface of the free ends 33-33 of the straps. .Fusible solder is poured between the clip 30 and straps HB-I2B to connect them together as a unit and the pressure exerted to the straps by the arms of the apparatus which are positioned in the opening 29 of the fuse, is in turn transmitted to the clips 30 and retained thereby until subjected to the proper degree of heat.

It will be noted, that in the forms of fuses disclosed, either or both ends may be released when subjected to a predetermined degree of heat. The release of one end or the other of the fuse will be equally effective to release the tensioned arms of the apparatus as the release of both ends of the fuse, thereby providing a dual control.

I claim:

1. A fusible link comprising opposing strap members, reversely formed of thin deformable material, spaced apart bearing shoulders on each strap member, the shoulders of one strap member being opposite those of the other, and fusible material connecting portions of the surfaces of said: strap members together, said shoulders being arranged to receive bearing pressure exerted in opposite, directions longitudinally of the strap members in the space between the bearing shoulders of each strap member.

'2. A fusible link comprising opposing strap members of thin deformable material, reversely formed, spaced apart bearing shoulders on each strap member, the shoulders of one strap member being opposite those of the other, said shoulders forming non-communicating chambers between the strap members, a retaining member in each of said chambers, and fusible material connecting portions of the surfaces of said strap members toeach other and connecting intermediate portions of the surfaces of said strap members to said retaining'members.

3. A fusible link comprising opposing: strap members of thin deformable materiaLreversely formed, spaced apart bearing shoulders on each strap member, theshouldersof one strap member being opposite those of the other,j'said shoulders forming non-communicating chambers between the strap members, a hollow, open ended retaining member in each of said chambers and fusible material connecting portions of the surfaces of said strap members to each other and connecting intermediate portions of the surfaces of said strap members to said retaining members.

4. Afusible link'comprising a pair of relatively thin strap members of deformable material formed to provide an abutment near each end thereof, a retaining member coasting with each abutments, and said strap members becoming abutment, and fusible material connecting the straightened by such pressure when the fusible strap members and retaining devices together, material is subjected to a degree of heat sufiithe abutments being arranged to receive bearcient to fuse the said material and release said ing pressure exerted in opposite directions longiretaining members. 5 tudinally of the strap members between said WILLIAM L. ROESSNER. 

